A. Indigenous Architecture as Basic Architectural Design 3.1.1 A POTENCY OF A LOCAL MATERIAL TO ACHIEVE A CREATIVITY Aulia Fikriarini Muchlis (1), Ernaning Setiyowati (2) (1) Architecture of UIN Maliki Malang, Indonesia [email protected] (2) Architecture of UIN Maliki Malang, Indonesia [email protected] ABSTRACT Local material used to be seen as a poor material. But nowadays, many architects try to explore the abilities of those material, so it can be used creativily in designing a sustainable building. It is one way to save the energy to deal with the global warming. One of the local material is bamboo. Bamboo is a sustainable material because it grows rapidly and it can be used in any building elements, from foundation to roof. Bamboo also have a capability in creating a thermal comfort inside a building. Many construction techniques are found, so bamboo can be used in a small buildings as well as big buildings, even in a long span buildings. Bamboo not only gives an aesthetic elements, but also a strong structure. Many great architectures now are made in bamboo. This paper shows some examples of buildings that use bamboo in creative ways. Keyword: local material, bamboo, creative I. INTRODUCTION The use of local material is one way to save the earth due to the global warming issue. By using such materials, people use less energy because it does not need an added transportation, and it only needs a local treatment. Most common people used to think that local material is tend to be used by poor community. But that opinion is changed lately, because so many great architecture are built by local material nowadays. So many techniques are found now in the same old local material. That is why the same local material that is used by local people, can be changed to be sophisticated material in the hand of an architect. There are many local materials available on earth, such as stone, wood, thatch, palm blare and bamboo. Those materials are available in every side of the world, only in a different kinds and characteristics. The most potential of local material is bamboo. It can be used in every part of a building, from foundation to roof. Bamboo is the largest of the grass family of plants. It grows very quickly, providing renewable material for building, tools, and utensils as well as edible shoots. Bamboo is particularly suitable for creating beautiful roof structures and is extremely resistant to earthquakes. Bamboo can replace wood and steel in many other situations as well. It can replace rebar, act as pins in straw bale construction, create trusses and other structural members, provide decorative elements, and even function as plumbing. Bamboo is susceptibleto insect damage, however, and must be treated for longevity. Sustainable forestry practices must also protect against over-harvesting. Although bamboo is considered a “poor person’s material”in many countries where it has been used vernacularly, that associationis changing as new structural systems allow for more ambitious architecture that is patronized by the wealthy (Kennedy, 2004). Bamboo is a local material in every place on earth. Worldwide there are about 1600 bamboo species distributed in about 121 genera (25 herbaceous and 96 woody). Geographically, these species are A-1 A. Indigenous Architecture as Basic Architectural Design found in the tropical, sub tropical and temperate areas of all the continents, except Europe where there are no indigenous species. The approximate continental distribution of bamboos is as follows: 67% in Asia and Oceania; 3% in Africa, and 30% in the Americas (Lopez, 2003). It shows that bamboo is easily to get and to be used in those places, and can be known as a local material. II. THE POTENCY OF BAMBOO AS A LOCAL BUILDING MATERIAL One of the ability of bamboo is as a building material. It can be used as a structure, a building surface, as well as an aesthetic element. So bamboo can be treated so many ways, depend on the need. Beside that, bamboo also has another potency in creating a thermal comfort inside a building. 2.1 Bamboo Preservation Before bamboo is used as a building material, it needs to be preserved first. Bamboo without preservation can survive for 10 years, so bamboo with preservation must survive longer than that. There are many ways to preserve bamboo, i.e: a. Bamboo preservation in general The best time for harvesting is the drier and cooler season when the insects are less active. b. Passive methods Simple constructive measures like lifting up the pillars or an outjutting roof can help to extend the life time of the bamboo distinctly. c. Active methods Smoking : Smoking it in its own resin. The smoke makes the rind unpalatable to insects which therefore decline the bamboo. Heating : The canes are heatted in kilns to ca. 150°C for a short time, so the structure of the outer zone changes and becomes more resistant against insects. The poles can crack up easily. When you cook bamboo, the starch and nutrient content will be reduced. Immersion : Freshly cut canes are immersed in water for 4-12 weeks. The nourishment for insects (starch and sugar) is removed. Streams are more suitable than stagnant ponds. Saltwater is not suitable, because the salt will stay in the bamboo and can bring moisture and fungi into the canes. Impregnating coatings : Coatings with borax are ecological and widely used. In addition, lime slurries, rangoo oil or slurries from lime or cow dung are also used. Using insectices is ecological not acceptable. These are kerosene, DDT, PCP and others. d. Aim These methods prevent the invasion of pests during changing the surface of the bamboo or remove the nourishment of the insects. To protect the bamboo from fungi and mould, the moisture must be kept away. To preservate the bamboo inside of the pole, all diaphragmas have to be perforated or all segments drilled. A-2 A. Indigenous Architecture as Basic Architectural Design 2.2. The Characteristic and Treatment of Bamboo Bamboo has many characteristic that makes it better than the other materials. The characteristic of bamboo are: a. Tensile strenght: The fibres of the bamboo run axial. In the outer zone are highly elastic vascular bundle, that have a high tensile strenght. The tensile strenght of these fibres is higher than that of steel, but its not possible to construct connections that can transfer these tensile strenghs. b. Shrinking: Bamboo shrinks more than wood when it loses water. The canes can tear apart at the nodes. Bamboo shrinks in the cross section ca. 10-16 %, in the wall thickness ca. 15-17 %. c. Fire resistance: The fire resistance is very good because of the high content of silicate acid. Filled up with water, it can stand a temperature of 400° C while the water cooks inside. d. Elasticity: The enormous elasticity of bamboo makes it to a very good building material for earth- quakeendangered areas. Another advantage of bamboo is its low weight. It can be transported and worked easily, the use of cranes is mostly unnecessary. Bamboo can be worked with the simplest tools wich must be especially sharp because of the highly silicified outer zone. Tool wear is considerably high. Recommendable methods are: a. Splitting: Very easy as long as it is splitted along the cane axis. The cane is split in halves and quarters and the driven apart by a wedge. It can also be split with a knife frame into four or eight segments. By means of splitting we get halved canes, strips and battens. To get planks, all the nodes are smashed and the wall of the pole is split over its entire length and forced open until the wall of the pole lies flat. Up to the age of 18 months, the canes can be peeled. The strips can be used as ties or be woven to make strings and ropes. Bamboo being forced to grow in a box b. Shaping: Bamboo which grows in a box gets a square shape. So it can be better used for connections. c. Bending: Freshly cut, bamboo can be bent and will keep this shape after drying. When heated above 150° C, bamboo keeps its shape after it goes cold. The surface area of bamboo also has to be treated in some ways. The informations about bleaching and dyeing are determined for small parts for kite-constructions. Bleeching and dyeing possibly can change the structure of the bamboo that far, it can´t support enough weigt. Nevertheless these methods should be introduced: a. Bleaching: Bleaching in hydrogen peroxide removes traces of resin or wax. If it stays in it too long, the bamboo will get perished. b. Dyeing: Every country has developed its own traditional method of dyeing. In principle: 1. Remove the wax, otherwise the colour can´t penetrate into the bamboo. 2. Bleach befor dyeing, so the colour will become more regular. 3. After dyeing, fix the colour in a solution of vinegar. A-3 A. Indigenous Architecture as Basic Architectural Design 2.3. Bamboo Construction Bamboo can be used as a structure, building surface, as well as an aesthetic elements. It can be used as a foundation, coloumn, floor, wall, roof truss, etc. Some bamboo construction technologies are shown in Figure 1. Some basic rules for using How to avoid the crushing of Types of joints used in bamboo in construction horizontal members bamboo construction Joints horizontal and vertical Fixing horizontal and Double and quadruple members vertical members with pins beams-supports and bolts Horizontal joints (not for structural members) Horizontal splicing (not for structural members) Figure 1.